title: Low number of detectable circulating tumor cells in non-metastatic colon cancer.
abstract: BACKGROUND
  The aim of the present study was to detect circulating tumor cells (CTCs) in the peripheral blood of patients with non-metastatic colon cancer and to evaluate whether there is a diurnal variation in the CTC counts. Furthermore, the study aimed to examine the correlation between CTCs and TNM stage, other paraclinical variables and prognosis.
  
  
  METHODS
  Blood samples were collected from 20 consecutive patients with colon cancer TNM stage I-III at four different perioperative time points. Detection of CTCs was performed using the immunological assay CellSearch®.
  
  
  RESULTS
  CTCs were detected in 1 out of 60 preoperative blood samples, resulting in a detection rate of 1 in 20 patients (5%; 95% confidence interval = 0.1-25%). None of the postoperative blood samples had CTC levels above the cut-off value (≥ 2 CTCs/7.5 ml blood).
  
  
  CONCLUSIONS
  The presence of CTCs in non-metastatic colon cancer is rare and barely detectable with the only commercially available assay for detection of CTCs, the CellSearch System.
authors.affiliation: Department of Surgery, Roskilde Hospital, University of Copenhagen, Koegevej 7-13, DK-4000 Roskilde, Denmark. moth@regionsjaelland.dk
authors.forename: Morten
authors.initials: M
authors.lastname: Thorsteinsson
authors.forename: György
authors.initials: G
authors.lastname: Söletormos
authors.forename: Per
authors.initials: P
authors.lastname: Jess
mesh_terms: D000230:Adenocarcinoma / Q000097:blood* / Q000473:pathology / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002940:Circadian Rhythm; D003110:Colonic Neoplasms / Q000097:blood* / Q000473:pathology / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000097:blood / Q000473:pathology; D009367:Neoplasm Staging; D009360:Neoplastic Cells, Circulating / Q000473:pathology*; D011446:Prospective Studies